Terminating easily and effectively coaxial electrical cables having non-metallic conductive polymeric shielding surrounding the metal center conductor and the primary dielectric insulating that conductor has been a source of problems in cable manufacture. No fail-safe mechanical interface has been developed and integral soldering has not been feasible. Conductive adhesives and conductive potting compounds have been tried with the attendant adhesive to metal bonding problem and the filling and curing times associated with the potting process.
In one instance, Schwartz, in U.S. Pat. No. 3,739,076, used a coil spring to evenly ground a braided metal outer shield of a coaxial cable to the connector such that each wire of the metal braid had the same firm, even equal, electrical contact with the connector as every other wire of the braid. A coil spring surrounding an electric conductive band was used by Taj, as shown in U.S. Pat. No. 4,032,205, to hold the band in contact with the metal tape shield of a high voltage cable. A conductive rubber sleeve surrounded the entire connector to form a water-tight seal.
Another grounding device for high-voltage cable was described in U.S. Pat. No. 3,777,050, by Silva, as a sleeve of conductive elastomeric material having a corrugated metal band and a grounding rod seated within the band. A bolt-tightened clamp was slipped over the conductive sleeve and the device placed over the metallic shielding tape of a coaxial cable and the clamp tightened to effect connection of the tape to the grounding rod.
A simple grounded conduit expansion joint is described by Browne in U.S. Pat. No. 3,154,632 in which a folded ring of copper braid is compressed ahead of the normal packing in the expansion joint to effect sliding electrical contact between the members of the joint as they are tightened together in a threaded closure.
An internally and externally threaded collar is used by Niketas as shown in U.S. Pat. No. 4,408,822 with a conical bushing having annular spurs to anchor the outer sheath and conductive outer shield of a coaxial cable as the conical bushing is inserted under the outer shield and the outer shield and sheath forcefully clamped between the conical bushing and threaded collar to effect connection of the cable.
The references principally show means for grounding power cables and a non-standard coaxial termination to a single grounding pin, which can lead to low shield effectiveness.